The invention relates to machines for making hot beverages, and more particularly to improvements in machines of the type wherein a liquid (such as water or milk) is heated by an electric heater and the thus heated liquid is caused to contact a metered quantity of comminuted coffee beans, tea leaves, chocolate powder or another flavoring agent in a holder whose outlet can dispense the resulting hot beverage into a vessel, such as a coffee pot. Still more particularly, the invention relates to improvements in machines wherein the electric heater heats the supply of liquid in a pressure-resistant container and a conduit, particularly a conduit including a riser, is employed to convey heated liquid from the interior of the container into the holder for a supply of flavoring agent.
German Offenlegungsschrift No. 2 428 165 discloses a household appliance which can be used as a coffee maker or as a tea making machine and wherein a pressure-resistant container for a supply of fresh water to be heated contains an electric heater which is located above the bottom wall of the container. A vessel above the container can be sealed to prevent the escape of aroma and comprises two chambers. One of the chambers serves to receive hot water from the container, and the other chamber contains a supply of coffee. The bottom wall of the one chamber is provided with a flow regulating device in the form of a solenoid-operated valve which at first prevents the hot beverage from leaving the vessel. A riser is provided to convey heated water from the container into the vessel; the inlet of the riser is closely adjacent the bottom wall of the container (i.e., it is close to the heater which is immersed in the supply of liquid in the container), and the riser extends through and beyond the top portion of the container so that its upper end is adjacent a removable cover for the vessel. The latter can constitute a portion of or the entire closure or cover for the container.
When the machine which is disclosed in the Offenlegungsschrift is put to use, the heater boils water in the container so that the pressure in the container rises and boiling water is compelled to flow up the riser and into the one chamber of the vessel on its way into contact with the flavoring agent. The flavoring agent is contacted by boiling water as long as the operator desires. To this end, the machine is equipped with a clock which can be set to open the solenold-operated valve after a selected interval of time so that the vessel can discharge the beverage into a pot or into another receptacle beneath the outlet which is controlled by the valve.
A drawback of the just described machine is that it requires a very long riser, namely a riser which extends from the bottom wall of the container for the supply of water to the cover or closure for the top of the vessel. The riser is fixedly secured to the cover for the container, i.e., to the bottom wall of the vessel if such bottom wall overlies and seals a portion of or the entire container. Therefore, it is not possible to shift the riser longitudinally and/or to otherwise change the orientation or position of the riser relative to the container and/or vessel. The electric heater in the container is a standard electric resistance heater which, as mentioned above, is installed directly in the water container. This necessitates the provision of expensive and rather complex means for preventing water from reaching the current-conveying parts of the heater. Moreover, the machine is set up exclusively for continuous operation, i.e., heated liquid forms a continuous stream which flows from the container into the vessel by ascending in the riser. Therefore, such machine does not permit a pulsating type of liquid flow such as is desirable for the making of certain beverages and involves the development of successive surges or swells of hot liquid. this drawback of the machine is attributable to inertia of the compact electirc resistance heater.
Certain other types of presently known machines for making coffee and/or other hot beverages employ thermostats, diodes, safety fuses and/or other auxiliary components which contribute to the cost, bulk and complexity of the heaters and render the machines prone to malfunction.